An underwater anti-interference electrochemical water quality sensor

Abstract

The present invention relates to the field of electronic information engineering technology, and discloses an underwater anti-interference electrochemical water quality sensor, comprising a signal conditioning module and a control module arranged in a waterproof housing, the signal conditioning module being electrically connected to a sensing electrode arranged at the bottom of the waterproof housing, the control module being electrically connected to an external host computer, and further comprising a wireless power supply component and a photoelectric isolation component, the wireless power supply component comprising a transmitting coil and a receiving coil arranged in parallel, the transmitting coil being electrically connected to the control module, and the receiving coil being electrically connected to the signal conditioning module; the photoelectric isolation component comprising a primary transceiver module, a secondary transceiver module and a light guide structure; the present invention adopts structural power supply isolation and digital signal isolation, which can realize simultaneous power supply and measurement of multiple underwater anti-interference electrochemical water quality sensors at close range, while solving the problem of mutual crosstalk that is prone to occur in detection of multiple water quality sensors carrying different electrochemical electrodes, and is not restricted by time and space.

Description

Technical Field

[0001] The invention relates to the technical field of electronic information engineering, and in particular to an underwater anti-interference electrochemical water quality sensor. Background Art

[0002] Electrochemical water quality sensors primarily consist of two components: sensing electrodes and measurement circuitry. The sensing electrodes are the sensor's core component, and different sensing electrodes can detect different substances. When the sensing electrodes come into contact with the substance being detected, an electrode reaction occurs, generating an electrochemical signal. This electrochemical signal is measured and analyzed by the signal conditioning module in the measurement circuitry, converted into an electrical signal related to the substance being detected, and transmitted for convenient monitoring.

[0003] When testing water quality using an electrochemical water quality sensor, due to the different substances that need to be detected, multiple water quality sensors carrying different detection electrodes are usually placed in the water for detection. However, when different detection electrodes (such as electrochemical dissolved oxygen, pH, ammonium ion, potassium ion and conductivity electrodes, etc.) are immersed in the test liquid at the same time for measurement, interference may occur between the circuit and signal transmission. The degree of interference depends on many factors, such as which electrode combination is used, which interface is used, whether the power interface is battery-powered or AC-powered, whether the communication interface is connected to a computer or operates as a standalone device, how far apart the electrodes are in the water, the conductivity of the water, etc.

[0004] To avoid crosstalk when multiple electrochemical water quality sensors with different electrodes are used for testing, two approaches are currently used. One is asynchronous power supply acquisition, which means that each electrochemical water quality sensor is individually controlled to supply power for testing. When one electrochemical water quality sensor completes testing, the next electrochemical water quality sensor is controlled to perform testing. The other is to arrange multiple electrochemical sensors at a large distance for measurement. However, both approaches have their own problems. The first requires step-by-step control of each sensor for testing, which results in cumbersome testing steps and low testing efficiency. The second approach, due to the large distances between the electrochemical water quality sensors, results in certain differences between their detection locations, making it difficult to achieve uniformity in water quality testing on a spatial and temporal scale. This greatly affects the analysis and prediction accuracy of spatiotemporal patterns of water quality in the monitored waters. Summary of the Invention

[0005] The purpose of the present invention is to provide an underwater anti-interference electrochemical water quality sensor to solve the problem of mutual crosstalk that is prone to occur when current electrochemical sensors work simultaneously, while being unrestricted by time and space and ensuring relatively accurate prediction accuracy.

[0006] The technical solution of the present invention is:

[0007] An underwater anti-interference electrochemical water quality sensor, comprising a signal conditioning module and a control module arranged in a waterproof housing, wherein the signal conditioning module is electrically connected to a sensing electrode arranged at the bottom of the waterproof housing, and the control module is electrically connected to an external host computer, and further comprising a wireless power supply component and a photoelectric isolation component, wherein the wireless power supply component comprises a transmitting coil and a receiving coil arranged in parallel, wherein the transmitting coil is electrically connected to the control module, and the transmitting coil is used to convert the current transmitted by the control module into an alternating magnetic field, and the receiving coil is electrically connected to the signal conditioning module, and the receiving coil is used to couple with the transmitting coil and generate current to the The signal conditioning module is powered; the optoelectronic isolation component includes a primary transceiver module, a secondary transceiver module and a light guide structure, the primary transceiver module includes a primary light emitter and a primary light receiver, the secondary transceiver module includes a secondary light emitter and a secondary light receiver, and the light guide structure is provided between the primary light emitter and the secondary light receiver, and between the secondary light emitter and the primary light receiver, the primary light emitter and the primary light receiver are electrically connected to the control module respectively, the secondary light emitter and the secondary light receiver are electrically connected to the signal conditioning module respectively, and the optoelectronic isolation component is used to achieve signal isolation.

[0008] Preferably, as a further improvement of the present invention, the distance between the transmitting coil and the receiving coil is 1 mm to 2 mm.

[0009] Preferably, as a further improvement of the present invention, the primary light emitter and the secondary light emitter are both LED emitters, the primary light receiver and the secondary light receiver are both photoelectric receiving tubes, the primary light receiver and the secondary light receiver are both photoelectric receiving tubes, and the primary light emitter and the secondary light receiver are coaxial and collinear, and the secondary light emitter and the primary light receiver are coaxial and collinear.

[0010] Preferably, as a further improvement of the present invention, the light-guiding structure arranged between the primary light emitter and the secondary light receiver includes a first light-guiding column and a second light-guiding column arranged coaxially and collinearly, and the light-guiding structure arranged between the secondary light emitter and the primary light receiver includes a third light-guiding column and a fourth light-guiding column arranged coaxially and collinearly, and the optical coupling end faces of the primary light emitter, secondary light emitter, primary light receiver, secondary light receiver, first light-guiding column, second light-guiding column, third light-guiding column and fourth light-guiding column are all sealed with transparent optical epoxy glue.

[0011] Preferably, as a further improvement of the present invention, the wavelength of the primary light emitter and the secondary light emitter is the same, and both are selected from any wavelength band between 450 nm and 750 nm.

[0012] Preferably, as a further improvement of the present invention, when optical communication is used for digital signal isolation, the data transmission rate is less than or equal to 9600 bps.

[0013] Preferably, as a further improvement of the present invention, the signal conditioning module is a signal conditioning board, which is provided with an amplifying and filtering circuit, an analog-to-digital conversion module and a microprocessor. The signal conditioning board is electrically connected to the sensing electrode, the receiving coil, the secondary light receiver and the secondary light transmitter respectively. The signal conditioning board converts the analog electrical signal into a high signal-to-noise ratio DC analog signal through the amplifying and filtering circuit, and converts the DC analog signal into a digital signal by controlling the analog-to-digital conversion module through the microprocessor.

[0014] Preferably, as a further improvement of the present invention, the control module is a control circuit board, and a pulse generator module and a power amplifier module are provided on the control circuit board. The pulse generator module and the power amplifier module are electrically connected. When the control circuit board is powered by an external DC power supply, the pulse generator module is controlled to output an AC signal. The operating frequency range of the AC signal is 30kHz to 50kHz. The AC signal passes through the power amplifier module to generate a magnetic field in the transmitting coil and the rated transmission power is less than or equal to 100mW.

[0015] Preferably, as a further improvement of the present invention, the waterproof shell includes a first shell, a second shell and a third shell arranged in sequence from top to bottom, the first shell and the second shell are detachably connected by threads, and the second shell and the third shell are detachably connected by threads.

[0016] Preferably, as a further improvement of the present invention, the sensing electrode is sealed and installed at the bottom of the third shell, the transmitting coil and the receiving coil are respectively vertically sealed and installed in the high-low coupling docking plug grooves provided in the first shell and the second shell, and the LED transmitter and the photoelectric receiving tube are both embedded in the high-low coupling docking plug grooves provided in the first shell and the second shell.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] The wireless power supply component set up can supply power in a non-contact manner, which can achieve power isolation. It can achieve stable energy supply during the process of the signal conditioning module converting and processing the electrochemical signals collected by the sensing electrodes, avoiding the problem of poor data acquisition accuracy caused by the interference of the mains frequency. The optoelectronic isolation component set up can use two sets of optical transceiver modules for modulation and demodulation to achieve digital signal isolation during signal transmission, and complete near-field wireless communication between the two sets of optical transceiver modules in the form of optical signals, effectively suppressing the interference and noise transmission of external circuits on the sensor signals, and basically eliminating the mutual crosstalk between the electrochemical electrodes. Therefore, through the coordination between power isolation and digital signal isolation measures, multiple underwater anti-interference electrochemical water quality sensors can be powered and measured simultaneously at close range. While solving the problem of mutual crosstalk that is prone to occur in the detection of multiple water quality sensors carrying different electrochemical electrodes, it can also ensure that the multiple water quality sensors are not far apart, thereby ensuring that the spatial and temporal scales are as unified as possible, thereby ensuring that the prediction accuracy is relatively accurate. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a schematic diagram of the explosion structure of an underwater anti-interference electrochemical water quality sensor according to an embodiment of the present invention.

[0020] Figure 2 This is a schematic diagram of a power supply implementation of an underwater anti-interference electrochemical water quality sensor according to an embodiment of the present invention.

[0021] Figure 3 The figure is a schematic diagram of digital communication implementation of an underwater anti-interference electrochemical water quality sensor according to an embodiment of the present invention. DETAILED DESCRIPTION

[0022] The following is combined with Figure 1 To the attached Figure 3 , a detailed description of the specific embodiments of the present invention is provided. In the description of the invention, it should be understood that the terms "center," "upper," "lower," "front," "back," "left," "right," "vertical," "horizontal," "top," "bottom," "inside," "outside," and the like, indicating directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings and are intended only to facilitate the description of the present invention and simplify the description. They do not indicate or imply that the devices or components referred to must have a specific direction, be constructed, or operate in a specific direction. Therefore, they should not be construed as limiting the present invention.

[0023] The terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the quantity of the technical features indicated. Therefore, features specified as "first" or "second" may explicitly or implicitly include one or more of such features; and in the description of the invention, unless otherwise specified, "plurality" means two or more.

[0024] Example

[0025] like Figures 1 to 3 As shown, an embodiment of the present invention provides an underwater anti-interference electrochemical water quality sensor, including a signal conditioning module 2, a control module 3, a wireless power supply component and a photoelectric isolation component arranged in a waterproof shell. The signal conditioning module 2 is electrically connected to the sensing electrode 4 arranged at the bottom of the waterproof shell, and is used to perform analog-to-digital conversion on the electrochemical signal collected by the sensing electrode 4. The control module 3 is electrically connected to the signal conditioning module 2 and an external host computer 307 respectively, and is used to receive the signal converted by the signal conditioning module 2 and transmit it to the external host computer 307; the wireless power supply component includes a transmitting coil 51 and a receiving coil 52 arranged in parallel. The transmitting coil 51 is electrically connected to the control module 3, and the transmitting coil 51 is used to convert the current transmitted by the control module 3 into an alternating magnetic field. The receiving coil 52 Electrically connected to the signal conditioning module 2, the receiving coil 52 is used to couple with the transmitting coil 51 and generate current to supply energy to the signal conditioning module 2; the optoelectronic isolation component includes a primary transceiver module, a secondary transceiver module and a light-guiding structure, the primary transceiver module includes a primary light transmitter 61 and a primary light receiver 62, the secondary transceiver module includes a secondary light transmitter 71 and a secondary light receiver 72, and a light-guiding structure is provided between the primary light transmitter 61 and the secondary light receiver 72, and between the secondary light transmitter 71 and the primary light receiver 62. The primary light transmitter 61 and the primary light receiver 62 are respectively electrically connected to the control module 3, and the secondary light transmitter 71 and the secondary light receiver 72 are respectively electrically connected to the signal conditioning module 2. The optoelectronic isolation component is used to achieve signal isolation and transmission.

[0026] In this embodiment, the sensor collects water quality information through the sensing electrode 4 and generates an analog electrical signal 41. The analog electrical signal 41 is received by the signal conditioning module 2 and subjected to analog-to-digital conversion processing. During the operation of the signal conditioning module 2, the wireless power supply component can be used to stably supply energy in a non-contact manner to achieve power isolation, thereby avoiding the problem of poor data collection accuracy caused by interference from the mains power frequency. The optoelectronic isolation component composed of the primary transceiver module, the secondary transceiver module and the light-guiding structure can form a symmetrical optical path in signal transmission, and optical communication can avoid the influence of electrical noise. It has a digital signal isolation function, thereby isolating the signal from the input end through modulation and demodulation, avoiding signal interference and transmission errors, effectively suppressing the interference and noise transmission of the external circuit on the sensor signal, and basically eliminating the mutual crosstalk between the electrochemical electrodes. The converted signal is transmitted to the external host computer 307 through the cable for monitoring and analysis. Therefore, in the process of using multiple underwater anti-interference electrochemical water quality sensors for measurement, the power supply isolation and digital signal isolation measures can realize the simultaneous power supply measurement of multiple underwater anti-interference electrochemical water quality sensors at a close distance, without the phenomenon of mutual crosstalk between electrodes.

[0027] Specifically, the signal conditioning module 2 is a signal conditioning board, which is provided with an amplifying and filtering circuit 203, an analog-to-digital conversion module 204 and a microprocessor 206. The signal conditioning board is electrically connected to the sensing electrode 4, the receiving coil 52, the secondary light receiver 72 and the secondary light transmitter 71 respectively. The signal conditioning board converts the analog electrical signal 41 into a high signal-to-noise ratio DC analog signal through the amplifying and filtering circuit 203, and controls the analog-to-digital conversion module 75 through the microprocessor 206 to convert the DC analog signal into a digital signal.

[0028] Among them, the analog-to-digital conversion module 204 is an ADC integrated chip, the amplification and filtering circuit 203 is a multi-stage amplification and filtering circuit, and the signal conditioning board converts the analog electrical signal 41 into a DC analog signal with a high signal-to-noise ratio through the multi-stage amplification and filtering circuit. The microprocessor 206 reads and writes the SPI interface circuit 205 and uses timing logic to control the ADC integrated chip to convert the DC analog signal into a digital signal.

[0029] Among them, the sensing electrode 4 can be one of the dissolved oxygen, pH, conductivity, ORP, ion-selective electrochemical electrodes, or one of the photoelectric detection electrodes such as turbidity, chlorophyll, optical dissolved oxygen, etc. The sensing electrode 4 is connected to the signal conditioning board through multiple bundles of wires.

[0030] The analog electrical signal 41 may be one or a combination of DC voltage, DC current, AC voltage, and AC current signals induced by a sensitive element.

[0031] Specifically, the control module 3 is a control circuit board, on which a pulse generator module 302 and a power amplifier module 303 are provided. The control module 3 is a control circuit board, on which a pulse generator module 302 and a power amplifier module 303 are provided. The pulse generator module 302 and the power amplifier module 303 are electrically connected. When the control circuit board is powered by an external DC power supply 301, the control pulse generator module 302 outputs an AC signal. The operating frequency range of the AC signal is 30kHz to 50kHz. The AC signal passes through the power amplifier module 303 to cause the transmitting coil 51 to generate a magnetic field and the rated transmission voltage is 0.04 V. The transmission power is less than or equal to 100mW, the surface distance between the transmitting coil 51 and the receiving coil 52 is controlled within 1mm to 2mm, and the receiving coil 52 is electrically connected to the signal conditioning board. When power is supplied, the receiving coil 52 passively generates an induced current under the condition of an alternating electromagnetic field generated by the transmitting coil 51. The induced current is rectified and filtered by the rectifier circuit 201 provided on the signal conditioning board to form a stable DC power supply voltage, and the voltage regulation is enabled to adjust the DC voltage to a stable voltage that can be used by the analog front-end circuit. The wireless charging field formed by the transmitting coil 51 and the receiving coil 52 has a different power reference ground source, so it has a power isolation function.

[0032] The pulse generator module 302 can be constructed using a dedicated chip, a single-chip microcomputer, or an operational amplifier integrated circuit. The transmission power can be adjusted by controlling the PWM frequency and duty cycle. The power amplifier is preferably constructed using a field-effect transistor.

[0033] Specifically, the primary light emitter 61 and the secondary light emitter 71 are both LED emitters, the primary light receiver 62 and the secondary light receiver 72 are both photoelectric receiving tubes, and the primary light emitter 61 and the secondary light receiver 72 are coaxial and collinear, and the secondary light emitter 71 and the primary light receiver 62 are coaxial and collinear.

[0034] Furthermore, the light-guiding structure arranged between the primary light emitter 61 and the secondary light receiver 72 includes a first light-guiding column 81 and a second light-guiding column 82 arranged coaxially and collinearly, and the light-guiding structure arranged between the secondary light emitter 71 and the primary light receiver 62 includes a third light-guiding column 83 and a fourth light-guiding column 84 arranged coaxially and collinearly. The first light-guiding column 81 and the second light-guiding column 82 are used to transmit the response instruction sent by the serial port of the microprocessor 206 set in the signal conditioning board to the serial port bus chip 306 set on the control circuit board. The upper computer 307 sends a read instruction through the serial port bus chip 306 on the control circuit board, and then transmits it to the serial port receiving end of the microprocessor 206 in the signal conditioning board through the third light-guiding column 83 and the fourth light-guiding column 84.

[0035] Among them, the optical coupling end faces of the primary light emitter 61, the secondary light emitter 71, the primary light receiver 62, the secondary light receiver 72, the first light guide column 81, the second light guide column 82, the third light guide column 83 and the fourth light guide column 84 are all sealed with transparent optical epoxy glue, specifically with two-component transparent optical epoxy glue OPT8217, and the optical glue OPT8217 has excellent light transmittance.

[0036] Furthermore, the wavelengths of the primary light emitter 61 and the secondary light emitter 71 are the same, and are both selected from any wavelength band between 450nm and 750nm. One of blue light, green light, yellow light, and near-infrared LED can be selected. The corresponding primary light receiver 62 and the secondary light receiver 72 should be selected from phototransistors with high sensitivity at the main wavelength of the LED.

[0037] Furthermore, a primary LED drive control circuit 305 and a primary photoelectric receiving tube control circuit 304 are provided on the control circuit board, and a secondary LED drive control circuit 207 and a secondary photoelectric receiving tube control circuit 208 are provided on the signal conditioning board. The primary LED drive control circuit 305 and the secondary LED drive control circuit 207 are both controlled by a direct control method in which the LED anode is connected to the pull-up resistor and the cathode is connected to the control signal. The control signal of the primary light emitter 61 is taken from the serial bus chip 306, and the control signal of the secondary light emitter 71 is taken from the serial output port of the microprocessor 206. The primary photoelectric receiving tube control circuit 304 and the secondary photoelectric receiving tube control circuit 208 both use a collector-connected pull-up resistor and an emitter-connected isolated ground. The collector of the primary photoelectric receiving tube 41 is connected to the serial bus chip 308, and the collector of the secondary photoelectric receiving tube 51 is connected to the serial output port of the microprocessor 206.

[0038] Furthermore, to ensure stable data transmission, when optical communication is used for digital signal isolation, the data transmission rate is less than or equal to 9600 bps.

[0039] In another embodiment of the present invention, in order to facilitate installation and seal and waterproof the internal devices, the waterproof shell includes a first shell 11, a second shell 12 and a third shell 13 arranged in sequence from top to bottom, and the first shell 11 and the second shell 12 are detachably connected by threads, and the second shell 12 and the third shell 13 are detachably connected by threads.

[0040] The sensing electrode 4 is encapsulated at the bottom of the third shell 13 by epoxy resin glue. The epoxy resin glue has the advantages of IP68 waterproof grade, strong insulation, aging resistance, strong corrosion resistance, and high temperature resistance.

[0041] Among them, the transmitting coil 51 is vertically installed in the first shell 11, and the receiving coil 52 is vertically installed on the second shell 12. Each coil is embedded in a pre-opened high-low coupling plug groove with white silicone, perpendicular to the horizontal plane. The receiving coil 52 is connected to the signal conditioning board through two wires, and the transmitting coil 51 is connected to the control circuit board through two wires.

[0042] The LED transmitter and the photoelectric receiving tube are both embedded in the high-low coupling plug grooves provided in the first shell 11 and the second shell 12 .

[0043] Among them, a waterproof connector 91 and a connector conversion assembly 92 are provided on the top of the first shell 11. The inner wall of the connector conversion assembly 92 is provided with a thread, and the waterproof connector 91 is provided with a thread. The connector conversion assembly 92 and the waterproof connector 91 are fastened by a threaded connection. The outer wall is smooth and is glued to the inner wall of the first shell 11 by glue. It is used to assemble the waterproof connector 91 and the first shell 11. The waterproof connector 91 prevents external liquid from entering the first shell 11 through the cable gap and damaging electronic components. The connector conversion assembly 92 is responsible for assembling the waterproof connector 91 and the first shell 11 together.

[0044] The second housing 12 and the third housing 13 are sealed and connected via a first sealing ring 93 and a second sealing ring 94 , which can prevent water from damaging electronic components after the waterproof housing is assembled.

[0045] In summary, the wireless power supply component set up in the present invention can supply power in a non-contact manner, realize power isolation, and realize stable energy supply in the process of the signal conditioning module converting and processing the electrochemical signal collected by the sensing electrode, thereby avoiding the problem of poor data acquisition accuracy caused by the interference of the mains frequency; the optoelectronic isolation component set up can adopt two sets of optical transceiver modules for modulation and demodulation to realize digital signal isolation during signal transmission, and complete near-field wireless communication between the two sets of optical transceiver modules in the form of optical signals, effectively suppressing the interference and noise transmission of the external circuit to the sensor signal, and basically eliminating the mutual crosstalk between the electrochemical electrodes; therefore, through the coordination between power isolation and digital signal isolation measures, multiple underwater anti-interference electrochemical water quality sensors can be powered on and measured at close range at the same time, while solving the problem of mutual crosstalk that is prone to occur in the detection of multiple water quality sensors carrying different electrochemical electrodes, it can also ensure that the multiple water quality sensors are not far apart, thereby ensuring that the spatial and time scales are as unified as possible, thereby ensuring that the prediction accuracy is relatively accurate.

[0046] The above disclosures are only several preferred specific embodiments of the present invention. However, the embodiments of the present invention are not limited thereto. Any changes that can be conceived by those skilled in the art should fall within the scope of protection of the present invention.

Claims

1. An underwater anti-interference electrochemical water quality sensor, comprising a signal conditioning module (2) and a control module (3) arranged in a waterproof housing, wherein the signal conditioning module (2) is electrically connected to a sensing electrode (4) arranged at the bottom of the waterproof housing, and is used to perform analog-to-digital conversion on the electrochemical signal collected by the sensing electrode (4); the control module (3) is electrically connected to the signal conditioning module (2) and an external host computer (307), respectively, and is used to receive the signal converted by the signal conditioning module (2) and transmit it to the external host computer (307), characterized in that: Also includes: A wireless power supply component, comprising a transmitting coil (51) and a receiving coil (52) arranged in parallel, wherein the transmitting coil (51) is electrically connected to the control module (3), and the transmitting coil (51) is used to convert the current transmitted by the control module (3) into an alternating magnetic field, and the receiving coil (52) is electrically connected to the signal conditioning module (2), and the receiving coil (52) is used to couple with the transmitting coil (51) and generate current to supply energy to the signal conditioning module (2); A photoelectric isolation component comprises a primary transceiver module, a secondary transceiver module and a light guide structure, wherein the primary transceiver module comprises a primary light transmitter (61) and a primary light receiver (62), and the secondary transceiver module comprises a secondary light transmitter (71) and a secondary light receiver (72), and the light guide structure is provided between the primary light transmitter (61) and the secondary light receiver (72), and between the secondary light transmitter (71) and the primary light receiver (62), respectively. The primary light transmitter (61) and the primary light receiver (62) are electrically connected to the control module (3), respectively. The secondary light transmitter (71) and the secondary light receiver (72) are electrically connected to the signal conditioning module (2), respectively. The photoelectric isolation component is used to achieve signal isolation and transmission; The primary light emitter (61) and the secondary light emitter (71) are both LED emitters, the primary light receiver (62) and the secondary light receiver (72) are both photoelectric receiving tubes, and the primary light emitter (61) and the secondary light receiver (72) are coaxial and collinear, and the secondary light emitter (71) and the primary light receiver (62) are coaxial and collinear; The light guide structure provided between the primary light emitter (61) and the secondary light receiver (72) comprises a first light guide column (81) and a second light guide column (82) which are coaxially arranged in a collinear manner, and the light guide structure provided between the secondary light emitter (71) and the primary light receiver (62) comprises a third light guide column (83) and a fourth light guide column (84) which are coaxially arranged in a collinear manner, and the optical coupling end faces of the primary light emitter (61), the secondary light emitter (71), the primary light receiver (62), the secondary light receiver (72), the first light guide column (81), the second light guide column (82), the third light guide column (83) and the fourth light guide column (84) are sealed and connected; The wavelengths of the primary light emitter (61) and the secondary light emitter (71) are the same and are both selected from any wavelength band between 450 nm and 750 nm.

2. The underwater anti-interference electrochemical water quality sensor according to claim 1, characterized in that: The distance between the transmitting coil (51) and the receiving coil (52) is 1 mm to 2 mm.

3. The underwater anti-interference electrochemical water quality sensor according to claim 1, characterized in that: When optical communication is used for digital signal isolation, the data transmission rate is less than or equal to 9600bps.

4. The underwater anti-interference electrochemical water quality sensor according to claim 1, characterized in that: The signal conditioning module (2) is a signal conditioning board, which is provided with an amplifying and filtering circuit (203), an analog-to-digital conversion module (204) and a microprocessor (206). The signal conditioning board is electrically connected to the sensing electrode (4), the receiving coil (52), the secondary light receiver (72) and the secondary light transmitter (71), respectively. The signal conditioning board converts the analog electrical signal (41) into a high signal-to-noise ratio DC analog signal through the amplifying and filtering circuit (203), and controls the analog-to-digital conversion module (204) through the microprocessor (206) to convert the DC analog signal into a digital signal.

5. The underwater anti-interference electrochemical water quality sensor according to claim 1, characterized in that: The control module (3) is a control circuit board. A pulse generator module (302) and a power amplifier module (303) are provided on the control circuit board. The pulse generator module (302) and the power amplifier module (303) are electrically connected. When powered by an external DC power supply (301), the control circuit board controls the pulse generator module (302) to output an AC signal. The operating frequency range of the AC signal is 30kHz to 50kHz. The AC signal generates a magnetic field in the transmitting coil (51) through the power amplifier module (303), and the rated transmission power is less than or equal to 100mW.

6. The underwater anti-interference electrochemical water quality sensor according to any one of claims 1 to 5, characterized in that: The waterproof housing comprises a first housing (11), a second housing (12) and a third housing (13) which are arranged in sequence from top to bottom. The first housing (11) and the second housing (12) are detachably connected by threads, and the second housing (12) and the third housing (13) are detachably connected by threads.

7. The underwater anti-interference electrochemical water quality sensor according to claim 6, characterized in that: The sensing electrode (4) is sealed and mounted on the bottom of the third shell (13); the transmitting coil (51) and the receiving coil (52) are respectively and vertically sealed and mounted in high-low coupling butt plug grooves provided in the first shell (11) and the second shell (12); and the LED transmitter and the photoelectric receiving tube are both embedded in the high-low coupling butt plug grooves provided in the first shell (11) and the second shell (12).

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